Google's pitch is that smartwatches can give wearers access to timely information — must-read messages, social media updates or directions — without them having to fish around in their pocket or bag to drag out their smartphone or tablet.

The Moto 360. Image: Motorola

Google sees health and fitness monitoring as one potentially big growth area for Wear — for example, fitness apps will be able to display real-time speed and distance travelled on wearable devices to give users an insight into their running or cycling regimes.

In future, Android Wear devices may also serve as remote controls for other devices, such as giving users the ability to launch a playlist on their phone or 'cast' a movie to their TV.

Google's Android Wear video (below) shows a range of scenarios where Android Wear watches might come in handy, from confirming a taxi pick up, to sending a jellyfish warning to someone about to go surfing. Other scenarios include sending a wearer updates on traffic on their route to work, or sending a QR-code boarding pass on a watch. Someone dancing even gets a popup notification asking if they'd like the watch to find out what the song is called.

It's hardly the first time tech companies have claimed smartwatches are the next big thing, but Google is working with consumer electronics manufacturers — including Asus, HTC, LG, Motorola and Samsung — and watch brands such as Fossil to put Android Wear watches in the market later this year, making this the most serious attempt yet.

Motorola is planning to launch the Moto 360, a round-faced timepiece, in the summer (it's pictured in the hipster setting above) while LG has showcased a video of the G Watch, which comes with a water-resistant square-faced watch with an 'always on' screen (below). It's expected to launch this quarter.

LG's G Watch. Image: LG

Because smartwatches have tiny screens and batteries compared to the plentiful real estate and processing power of a phablet, Google has rethought the Android user interface and stripped it back to conserve power — and stop smartwatches driving users crazy with constant updates.

Android Wear builds on the existing notification system used by Android apps, giving devices a 'context stream' made up of a vertically-scrolling list of 'cards' carrying small pieces of information, similar to those seen in Google Now. For example a card might carry a message from a friend, or a weather forecast. Wearers swipe vertically through these notification cards to find the ones they want.

Android Wear notifications. Image: Google.

The cards can also be swiped sideways to show more information on additional cards. Google calls these extra cards 'pages'. The first card from a weather app might show today's weather, with an extra page adding a three-day forecast, for example.

Developers can build these card alerts into their apps so they can be injected into the stream when they are relevant. These notifications can be triggered by contextually for example geofences can be used to pop up information when the wearer arrives home, or developers can use Android's activity detection APIs to send a messages when they are cycling or running.

An example of an Android Wear alert. Image: Google.

Google wants developers to emphasise "glanceable" updates that provide "the maximum payload of information with a minimum of fuss". And, rather than risk wearers making mistakes when poking fat fingers at tiny screens, Google said "inputs requiring fine-grained motor skills" should be avoided and recommends interaction based around swipes or voice.

Google is also keen to stop apps from being too irritating. "Be respectful of users' attention and aware of how unnecessary interruptions will reflect on your application's reputation," its guide for developers advises. That means notifications that make your watch vibrate should be limited to situations where urgent action is needed: others should just silently add to the card stream.

Smartwatch sending message. Image: Google.

Smartwatches have been tried before and failed — the technology wasn't ready (limited battery life was a problem, and few people were willing to charge their watch every day), and wearers struggled to see the point of them. However, growing enthusiasm for fitness bands (such as the Nike+ FuelBand, Jawbone UP, and Fitbit devices) may indicate consumers are ready to embrace wearables this time around.

More importantly (at least for them and their shareholders) consumer electronics companies need a new moneyspinner now the smartphone market is showing signs of saturation. Nobody is sure that smartwatches are the answer, but persistent rumours that Apple is working on an 'iWatch' means that most smartphone makers feel obliged to have a plan for wearables too.

More than 19 million wearable devices will be shipped this year according to analyst IDC — triple the number shipped last year — and the analysts predicts this will grow to 112 million units by 2018.

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Cheap, simple to use fitness bands will continue to lead the market, according to analyst IDC. What the analyst describes as 'smart accessories' like smartwatches (so-called because they need a smartphone or tablet to work) will make up another chunk of the market. However, "their value proposition has yet to be completely clarified", IDC added with some understatement.

"While not quite ready for prime time, the smart accessory market will continue to mature as users better understand and accept the value proposition and vendors refine their offerings," IDC said. In other words, manufacturers are trying to figure out what works, and consumers are still figuring out whether they really want another gadget to worry about.

The third and least developed segment of the market is fully autonomous wearables such as Google Glass, which don't need the wearer to be toting a phone as well; it could be years before these types of device are selling in significant numbers. And it may be that businesses rather than consumers are the first to jump in here.

"To succeed, smart wearable vendors must convince users to shift to a new user experience while offering them a robust selection of third-party applications. It is not a question of 'if,' but 'when' wearables as a whole will extend into the enterprise," the analyst said.

And getting consumers to buy smartwatches is only the first step. Research suggests that most of these devices get dumped pretty quickly after being bought — the high tech version of joining a gym and only going once. Turning them from novelties into useful devices is one of the biggest challenges.

The Pebble smartwatch. Image: Pebble.

Android Wear isn't the only game in town either. Samsung (pointedly missing from the initial set of Android Wear supporters even though it's the biggest Android maker) has been experimenting with the Android rival Tizen OS on its Gear 2 smartwatch. Other smartwatch players include Pebble and Sony's smartwatch, and Microsoft is also rumoured to be working on a timepiece. Can Android Wear create the critical mass to make wearables a reality? Watch this space.